Pilot wrench



T. PURNIS PILOT WRENCH Dec'. 3, 1935.

Filed June 22, 1955 ZZeS @f 3H m W @Mud W mi; W 4 0 /M Patented Dec. 3, 1935 UNITED STATES PATENT A(')FFICE 2 Claims.

Known machines for grinding the valve seats of internal combustion engines, for instance the machine shown in Patent 1,948,792, granted on February 27, 1934, operate upon and about a pilot rod which is securedin the valve stem bushing of the engine. Such machines have been perfected to a point where the grinding of the seat takes less time than the placing of the pilot, and this invention aims to provide a wrench which will enable the pilot to be placed quickly. The invention aims to provide novel means for coupling the wrench to the pilot, uncoupling the wrench from the pilot, and imparting rotation to the pilot by way of the wrench.

It is within the province of the disclosure to improve generally and to enhance the utility of devices of that type to which the invention appertains.

With the above and other objects in view, which will appear as the description proceeds, the invention resides in the combination and arrangement of parts and in the details of construction hereinafter described and claimed, it being understood that changes in the precise embodiment of the invention herein disclosed, may be made within the scope of what is claimed, without departing from the spirit of the invention.

In the accompanying drawing:

Fig. 1 shows in elevation, a wrench constructed in accordance with the invention, the wrench being assembled with the pilot, and the pilot being mounted in the valve stem bushing of an internal combustion engine;

Fig. 2 is a longitudinal section showing the wrench latch to the pilot;

Fig. 3 is a longitudinal section showing the wrench set to receive the pilot, the pilot being in the position it will assume when it is about to actuate the plunger and enable the latches to engage the pilot.

The numeral I marks a portion of an internal combustion engine, carrying a bushing 2, in which reciprocates the stem of the poppet valve (not shown), the Valve being adapted to cooperate with the seat shown at 3.

The pilot rod 4 is provided with a keeper, such as a transverse hole 5, and has an upper tapered part 6, a threaded lower tip 'I and a tapered lower part 8. A split sleeve 9 is threaded on the tip 'I. When the pilot`4 is rotated, the tapered part 8 expands the bushing 2, the tapered part 6 is wedged in the upper end of the bushing, and the pilot is held securely in the bushing. The wrench forming the subject matter of this application is assembled with the pilot 4, and is used rst to place the pilot in the bushing 2, and then to rotate the pilot and secure it in place.

The wrenchpcomprises p. tubular body II), to

one end of which a disk or handll'lssecuredrv The body I0 has superficial longitudinal grooves 5 I2, receiving spring tongues I4. At their upper ends, the tongues I4 have ngers I 5 engaged with the body I0, and the body is dented in at I6, to engage the tongues. The upper portions of the tongues I4 thus are secured to the body I0, but 10 the lower portions of the tongues are free for in and out movement.

The lower ends of the spring tongues I4 are v mounted somewhat loosely in openings in tapered latches I1, mounted to slide in the body Il) trans- 15 versely thereof, and to enter the bore of the body. Detents I 8, preferably balls, aremounted to move in the body, transversely thereof, and to enter the bore of the body, the detents being located intermediate the ends of the spring tongues I4. 20

The detents I 8 are disposed between the spring tongues I4 and the plunger I9 mounted in the body I0, the plunger and the body having relative longitudinal sliding movement. The plunger I9 has a circumferential seat 20 and is provided with 25 a tapered part 2|,.forming the upper portion of the seat 20.

When the device is in the position of Fig. 3, the detents I8 engage spring tongues .I4 and engage the plunger I9, in its cylindrical portion, 30 above the tapered part 2I, and hold the spring tongues in downwardly diverging relation, the latches I'I being retracted. The pilot 4 is introduced into the body I0 of the wrench and pushes the plunger 'I9 upwardly until the seat 20 is in 35 the same plane with the detents I8, transversely of the body I0. When the detents I8 enter the seat 20, the tongues I4 spring inwardly, and the latches I'I engage in the hole 5 of the pilot 4.

The wrench then is coupled to the pilot 4 and 40 may be used to introduce the pilot into the bushing 2, and to rotate the pilot, thereby anchoring the pilot in place as hereinbefore described.

When reverse rotation is imparted to the wrench, the pilot 4 may be released from the 45 bushing 2 and be lifted out of the bushing. Assuming that the parts then are in the position of Fig. 2, the operator engages his rst and second fingers under the disk II and places his thumb on the upper end of the plunger I9. The 50 plunger I9 is thrust downwardly, the tapered part 2l of the plunger or slide engages the detents I8 and carries them outwardly, the spring tongues I4 being swung outwardly, the latches II being I, withdrawn from the seat 5 in the pilot 4, the pilot 5 4 being set free, and the wrench being restored to the set position of Fig. 3, ready for another operation.

The device is simple in construction but it constitutes a means whereby time can be saved in the mounting of the pilot 4 in the bushing 2 of an internal combustion engine.

Having thus described the invention, what is claimed is:

1. A pilot wrench comprising a tubular body, a latch movable in the body, a detent movable in the body, a plunger movable in the body, spring means for advancing the latch, the detent being interposed between the plunger and the spring means, the plunger comprising a part which engages the detent to hold the latch retracted, and the plunger having a seat into which the detent can retire, when the plunger is shifted from detent holding position, thereby to permit the latch to be advanced by the spring means.

` 2. A pilot wrench comprising a tubular body, a latch movable in the body, a detent movable in the body, a plunger movable in the body, spring means for advancing the latch, the detent being interposed between the plunger and the spring means, the plunger comprising a part which engages the detent to hold the latch retracted, the plunger having a, seat into which the detent can retire, when the plunger is shifted from detent holding position, thereby to permit the latch to be advanced by the spring means, the plunger comprising an inclined part which cooperates With the detent to retract the detent when the plunger is moved toward detent holding position.

THEODORE PURNIS. 

